The present invention relates to a conveyor system utilizing the linear motor for driving conveyor carts, and more particularly to a conveyor system comprising a conveyor cart, a guide rail for movably supporting the conveyor cart, primary coils mounted on the guide rail and a secondary conductor mounted on the conveyor cart.
Conventionally the secondary conductor mounted on the conveyor cart is formed of a single plate. There are a case where the linear motor comprises a secondary conductor mounted horizontally on the conveyor cart and a case where the linear motor comprises a secondary conductor mounted vertically on the conveyor cart. The former is suited for use with a running track including horizontal curves, while the latter is suited for use with a running track including vertical curves.
Furthermore, the primary coils are arranged at appropriate intervals longitudinally of the guide rail in some cases, and in continuous series longitudinally of the guide rail in other cases. In the former case it is desirable that the primary coils have a good length in order to prolong a period of acceleration or deceleration effected by the intermittently arranged primary coils. In the latter case too it is desirable that the primary coils have a good length in order to provide a strong propulsive force.
In addition, such an article conveyor system that drives the conveyor carts to stations disposed at various locations has the guide rail curved in horizontal and vertical directions to define horizontally curved and vertically curved running track portions. It is desirable for such curved track portions to have the smallest possible radius of curvature in order to achieve high conveying efficiency.
However, the conventional construction including the secondary conductor formed of a single plate having a large length has the disadvantage that the radius of curvature at the curved running track portions cannot be reduced to a satisfactory degree. Where, for example, the secondary conductor is placed to move through an interior space of the guide rail, it is necessary to avoid a collision between the secondary conductor and the guide rail. Where the conveyor cart is driven by the linear motor also at the curved track portions, it is necessary to maintain the entire secondary conductor in a proper position relative to the primary coils.